Swamp Thing was created by Len Wein and Berni Wrightson. He first appeared in House of Secrets #92 in a stand-alone horror story set in the early 20th century. The Swamp Thing then returned in his own series, set in the contemporary world. The character is a humanoid mass of vegetable matter who fights to protect his swamp home, the environment in general, and humanity from various supernatural or terrorist threats.

Along with Forbidden Tales of Dark Mansion, Swamp Thing headed DC's line of horror comics of the 1970s.